/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2015 Thomas Braun, Jens Klingen, Robin Krom
 *
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using Greenshot.Drawing.Fields;
using Greenshot.Helpers;
using Greenshot.Plugin.Drawing;
using System;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace Greenshot.Drawing
{
    /// <summary>
    /// Description of EllipseContainer.
    /// </summary>
    [Serializable()]
    public class EllipseContainer : DrawableContainer
    {
        public EllipseContainer(Surface parent) : base(parent)
        {
        }

        protected override void InitializeFields()
        {
            AddField(GetType(), FieldType.LINE_THICKNESS, 2);
            AddField(GetType(), FieldType.LINE_COLOR, DefaultLineColor);
            AddField(GetType(), FieldType.FILL_COLOR, Color.Transparent);
            AddField(GetType(), FieldType.SHADOW, true);
        }

        public override void Draw(Graphics graphics, RenderMode renderMode)
        {
            graphics.SmoothingMode = SmoothingMode.HighQuality;
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.CompositingQuality = CompositingQuality.HighQuality;
            graphics.PixelOffsetMode = PixelOffsetMode.None;

            int lineThickness = GetFieldValueAsInt(FieldType.LINE_THICKNESS);
            Color lineColor = GetFieldValueAsColor(FieldType.LINE_COLOR);
            Color fillColor = GetFieldValueAsColor(FieldType.FILL_COLOR);
            bool shadow = GetFieldValueAsBool(FieldType.SHADOW);
            Rectangle rect = GuiRectangle.GetGuiRectangle(Left, Top, Width, Height);
            DrawEllipse(rect, graphics, renderMode, lineThickness, lineColor, fillColor, shadow);
        }

        /// <summary>
        /// This allows another container to draw an ellipse
        /// </summary>
        /// <param name="caller"></param>
        /// <param name="graphics"></param>
        /// <param name="renderMode"></param>
        public static void DrawEllipse(Rectangle rect, Graphics graphics, RenderMode renderMode, int lineThickness, Color lineColor, Color fillColor, bool shadow)
        {
            bool lineVisible = (lineThickness > 0 && Colors.IsVisible(lineColor));
            // draw shadow before anything else
            if (shadow && (lineVisible || Colors.IsVisible(fillColor)))
            {
                int basealpha = 100;
                int alpha = basealpha;
                int steps = 5;
                int currentStep = lineVisible ? 1 : 0;
                while (currentStep <= steps)
                {
                    using (Pen shadowPen = new Pen(Color.FromArgb(alpha, 100, 100, 100)))
                    {
                        shadowPen.Width = lineVisible ? lineThickness : 1;
                        Rectangle shadowRect = GuiRectangle.GetGuiRectangle(rect.Left + currentStep, rect.Top + currentStep, rect.Width, rect.Height);
                        graphics.DrawEllipse(shadowPen, shadowRect);
                        currentStep++;
                        alpha = alpha - basealpha / steps;
                    }
                }
            }
            //draw the original shape
            if (Colors.IsVisible(fillColor))
            {
                using (Brush brush = new SolidBrush(fillColor))
                {
                    graphics.FillEllipse(brush, rect);
                }
            }
            if (lineVisible)
            {
                using (Pen pen = new Pen(lineColor, lineThickness))
                {
                    graphics.DrawEllipse(pen, rect);
                }
            }
        }

        public override bool Contains(int x, int y)
        {
            return EllipseContains(this, x, y);
        }

        /// <summary>
        /// Allow the code to be used externally
        /// </summary>
        /// <param name="caller"></param>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        public static bool EllipseContains(DrawableContainer caller, int x, int y)
        {
            double xDistanceFromCenter = x - (caller.Left + caller.Width / 2);
            double yDistanceFromCenter = y - (caller.Top + caller.Height / 2);
            // ellipse: x^2/a^2 + y^2/b^2 = 1
            return Math.Pow(xDistanceFromCenter, 2) / Math.Pow(caller.Width / 2, 2) + Math.Pow(yDistanceFromCenter, 2) / Math.Pow(caller.Height / 2, 2) < 1;
        }

        public override bool ClickableAt(int x, int y)
        {
            int lineThickness = GetFieldValueAsInt(FieldType.LINE_THICKNESS) + 10;
            Color fillColor = GetFieldValueAsColor(FieldType.FILL_COLOR);
            Rectangle rect = GuiRectangle.GetGuiRectangle(Left, Top, Width, Height);
            return EllipseClickableAt(rect, lineThickness, fillColor, x, y);
        }

        public static bool EllipseClickableAt(Rectangle rect, int lineThickness, Color fillColor, int x, int y)
        {
            // If we clicked inside the rectangle and it's visible we are clickable at.
            if (!Color.Transparent.Equals(fillColor))
            {
                if (rect.Contains(x, y))
                {
                    return true;
                }
            }

            // check the rest of the lines
            if (lineThickness > 0)
            {
                using (Pen pen = new Pen(Color.White, lineThickness))
                {
                    using (GraphicsPath path = new GraphicsPath())
                    {
                        path.AddEllipse(rect);
                        return path.IsOutlineVisible(x, y, pen);
                    }
                }
            }
            return false;
        }
    }
}